Unresolved reference error with Kotlin 2.1 and API dependencies

[vinceglb]

After upgrading my library from Kotlin 2.0.21 to 2.1.0, my build broke. After some investigation, I realized that the plugin was breaking the build in a specific case: when using api dependencies. Here is the setup:

Library root

gradle/libs.versions.toml

kotlin = "2.1.0"
vanniktech-mavenPublish = "0.30.0"

Then, configure the POM as described here: https://vanniktech.github.io/gradle-maven-publish-plugin/central/#configuring-maven-central

gradle.properties

...

# OSS
SONATYPE_HOST=S01
RELEASE_SIGNING_ENABLED=true

# Lib
GROUP=...
VERSION_NAME=...

POM_NAME=...
POM_DESCRIPTION=...

... continue to apply configs

Package lib-a

LibA.kt

class LibA

Package lib-b

build.gradle.kts

plugins {
    alias(libs.plugins.kotlinMultiplatform)
    alias(libs.plugins.androidLibrary)
    alias(libs.plugins.vanniktech.mavenPublish)
}

kotlin {
    ...
    sourceSets {
        commonMain.dependencies {
            // Uses api here
            api(projects.libA)
        }
    }
    ...
}

Package lib-c

build.gradle.kts

plugins {
    alias(libs.plugins.kotlinMultiplatform)
    alias(libs.plugins.androidLibrary)
    alias(libs.plugins.vanniktech.mavenPublish)
}

kotlin {
    ...
    sourceSets {
        commonMain.dependencies {
            implementation(projects.libB)
        }
    }
    ...
}

main.kt

fun main() {
    val lib = LibA()   // Unresolved reference: LibA with Kotlin 2.1.0 but works with Kotlin 2.0.21
}

---

I realized that:

• if I use Kotlin 2.0.21, everything will work as expected.
• if I remove the plugin configs from the gradle.properties, even when using Kotlin 2.1, it fixes the build with no more unresolved reference error.

If you have any questions, don't hesitate!

[gabrielittner]

Could you share a project that reproduces it?

[vinceglb]

Sure, here is a reproduction repository: https://github.com/vinceglb/MavenPublishExample

You can visit LibC.kt or App.kt to see errors in Android Studio.

Also, you can run one of these commands to have errors at build time:

./gradlew build
./gradlew :lib-c:compileCommonMainKotlinMetadata

If you remove all the plugin properties bellow # OSS in gradle.properties, it will fix the problem.

Also, if you keep properties in gradle.properties but downgrade kotlin to 2.0.21, it will fix the problems too.

[gabrielittner]

Thank you for the reproducer, it helped a lot. I was able to narrow it down to the GROUP property and then was also able to generally reproduce it with the regular maven-publish plugin. In particular setting the groupId on the kotlinMultiplatform publication (this is the "common" artifact that gets published) will trigger the issue. I've filed an issue in the Kotlin issue tracker for this https://youtrack.jetbrains.com/issue/KT-73620

[vinceglb]

Thanks a lot for your reactivity! I'll follow the issue on YouTrack.